It might be a bit difficult to get OO scale British prototypes if you’re limited to what you can get in the US but it is possible. I’ve seen the Hornby Black Five being sold new on eBay for around $100 USD shipped. I *think* a couple of the bigger importers/retailers like Reynauld’s and Walthers carry some OO scale stuff, so that might be a possibility.
Much as I love steam, I would be tempted to go with an all diesel locomotive fleet. You mentioned the Class 08 and I would consider Class 03, Class 04 and Class 07 as well as the larger Class 20. Other good choices would be the Class 40 and the Class 42 “Warship” (aka Diesel 10).
If money and product availability are factors, and since you mentioned being in the US, have you considered modeling US prototypes in HO scale? I would NEVER discourage you from using the equipment you want but that’s the direction I ultimately chose with my own model railroad project. I considered British prototypes, as well as European, Japanese and even “foreign export” locomotives like the EMD G8 and G12. Even with a fairly small railroad, it ended up being a lot easier and cheaper to use 50s-60s era US engines. For me, it wasn’t just the locomotives and rolling stock but also the accessories, figures, buildings and that sort of thing.
Much as I love steam, I would be tempted to go with an all diesel locomotive fleet. You mentioned the Class 08 and I would consider Class 03, Class 04 and Class 07 as well as the larger Class 20. Other good choices would be the Class 40 and the Class 42 “Warship” (aka Diesel 10).
If money and product availability are factors, and since you mentioned being in the US, have you considered modeling US prototypes in HO scale? I would NEVER discourage you from using the equipment you want but that’s the direction I ultimately chose with my own model railroad project. I considered British prototypes, as well as European, Japanese and even “foreign export” locomotives like the EMD G8 and G12. Even with a fairly small railroad, it ended up being a lot easier and cheaper to use 50s-60s era US engines. For me, it wasn’t just the locomotives and rolling stock but also the accessories, figures, buildings and that sort of thing.